The goal of the course is to take the students from the active amplifiers designed with different trasistor types, into the concept of negative feedback. This is a fundamental technique in engineering electronics to reduce the impact of the parameter dispersion of the transistor (component) onto the amplifier (system) characteristics: gain, input impedance and output impedance. Once the advantages of negative feedback are clear, and the analysis techniques explained, the course covers a major issue of of feedback. The impact of feedback on the amplifier stability, through the appearance of positive feedback at given frequencies. Means to overcome oscillation are shown. The last part of the course deals with the use designing circuits with positive feedback to develop linear oscillators, in which a signal at a desired frequency is self generated.